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2 years ago

Phosphoric acid has a pka of 2.1. at what ph will 75% of phosphoric acid be in the conjugate base form?

Chemistry

2 answers:

Colt1911 [192]2 years ago

8 0

Answer:

pH is 2.58

Explanation:

The pH of the buffer made from the mixture of phosphoric acid (H₃PO₄) and its conjugate base form (H₂PO₄⁻) follows the Henderson-Hasselbalch equation:

pH = pka + log [H₂PO₄⁻] /[H₃PO₄]

If 75% of the buffer is in the conjugate base form (H₂PO₄⁻), 25% will be as H₃PO₄. Replacing to find pH:

pH = 2.1 + log [75%] /[25%]

pH = 2.58

EleoNora [17]2 years ago

5 0

solution:

$from henderson hasselbalch equation\\pH=pka+log[\frac{conjugate}{acid}]\\given[\frac{conjugate base}{acid}]\\=\frac{75}{25}=3\\PH=2.1+log3\\pH=2.1+0.5=2.6$

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In step 6, khp was dissolved in a trivial amount of deionized h2o prior to titration with naoh. why was it acceptable to use an

nadya68 [22]

Water acts as solvent and it has no effect on the amount of the acid or the titrating agent.
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2 years ago

In thionyl chloride, cl2so (s is the central atom), the formal charge on sulfur and number of lone pairs on sulfur are, respecti

zimovet [89]

Sulfur in the thionyl compound will have the formal charge or +1 and has two lone electrons or one lone pair.

<h2>Further Explanation</h2><h3>Lewis Structures</h3>

In order to determine the formal charge and number of lone pairs, it is imperative to draw the Lewis structure first. The steps in drawing the lone pairs are:

Get the total number of valence electrons by adding the number of valence electrons of each atom in the compound.
Determine the central atom.
Place the other atoms around the central atom and connect each to the central atom by a single bond. For every single bond, 2 electrons from the total valence electrons are shared.
Distribute the remaining valence electrons to the terminal atoms. Start by distributing to one terminal atom until the atom has an octet then move to the next terminal atom. If all terminal atoms have an octet, the remaining electrons will be placed in the central atom.

For thionyl chloride, the central atom is sulfur and the total number of valence electrons is:

Cl = 7 × 2 = 14

S = 6

O = 6

Total Valence Electrons = 14 + 6 + 6 = 26 electrons. Following the steps above, the resulting Lewis structure is shown in the attachment.

Once the Lewis structure is known, the number of lone pairs in the central atom can be known. For thionyl chloride, it can be seen that there are two unshared electrons in S. Therefore, S has one lone pair.

<h3>Formal Charges</h3>

The relative distribution of electrons in a molecule can be described through the formal charges of each atom. The formal charge describes how many electrons there are in an atom compared to how many electrons it has if it were not bonded. For a molecule to have a stable structure, the formal charges of all the atoms must be at the lowest possible values.

The formula to determine the formal charge is:

Formal Charge = # valence electron for the isolated atom - (# bonds + non-bonding electrons)

For the thionyl compound, the formal charge of S is determined using the following equation and by looking at the Lewis Structure:

Valence Electrons of a Sulfur atom = 6
Number of bonds around Sulfur = 3
Number of non-bonding electrons on Sulfur = 2

Formal Charge of S = 6 - (3+2)

Formal Charge of S = +1

This means that sulfur has less electrons around it in the molecule than it has as an isolated atom.

<h3>Learn More</h3>

Lewis Structure brainly.com/question/2323095
Valence Electrons brainly.com/question/2376134

<em>Keywords: formal charge, lone pairs</em>

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2 years ago

Read 2 more answers

According to the VSEPR model, the arrangement of electron pairs around NH3 and CH4 is A. the same, because in each case there ar

aleksklad [387]

Answer:

Option "B" is correct.

Explanation:

According to VSEPR theory, There are repulsion forces exists among the bond pair - bond pair or bond pair - lone pair of electrons. In $NH_{3}$ and $CH_{4}$ , the number of electron pairs are same but methane has all the four bond pairs where in ammonia, three bond pairs and one lone pair exists. And thus there are repulsion forces possible in between the lone pair and bond pair of electrons thus the arrangement of electron pairs around both the molecules is same or different depending up on the conditions leading to maximum repulsion.